The present invention relates generally to nondestructive testing methods utilizing ultrasonics, and more particularly to improved system and method for in-process monitoring of resin cure within composite sheet material during fabrication.
The invention provides system and method for acousto-ultrasonic monitoring of the cure of resin impregnated fabric composite materials during fabrication thereof. The invention is useful particularly for monitoring the cure of phenolic resin based composite materials in the processing environment. In accordance with the teachings hereof, composite sheet material being monitored is impressed with an ultrasonic pulse and the attenuation of the resultant transient elastic stress wave is observed after it has passed through the material. The incident ultrasonic wave is generated by applying a voltage pulse across a first piezoceramio transducer. The compression wave thus produced is received by a second piezoceramic transducer which generates an output voltage signal characteristic of the attenuation of the wave passing through the material. Change in output of the second transducer is directly related to propagation efficiency of the medium between the first and second transducers. For a given material, the propagation efficiency is directly related to the condition of the material along the propagation path.
It is therefore a principal object of the invention to provide an improved ultrasonic nondestructive testing system and method.
It is a further object of the invention to provide an improved nondestructive ultrasonic testing system and method for in-process testing of composite materials.
It is yet another object to provide system and method for in-process monitoring of resin cure during composite fabrication.
These and other objects of the invention will become apparent as the detailed description of representative embodiments proceeds.